Liquid noise after switching off engine

[Tommie_a]

Hi guys just got back from a drive in my 172.

popped the hood to plug the charger on the battery as I probably won’t drive her for a few weeks now, heard a noise like water moving around near the back of the engine (see video)



any ideas what it is? In my head it was trapped air in the coolant or something… Went on for a few minutes. Clio is boosted by way by ED and running great

Pardon my ignorance and thanks in advance
Tom

 

[JamesBryan]

Does it have an external water pump for the turbo, like the Megane does?

 

[Tommie_a]

I don’t believe so no!

 

[Yarp]

I had similar with mine when the water feeds went to/from the heater matrix. I moved the return to go to the pipe that goes back to the coolant bottle and that stopped it. I think the turbo was boiling the water and it had nowhere to go with the pressure from the rest of the system.

 

[Tommie_a]

Thanks for your reply, I will look into this 😊

 

[Brigsy]

Localised boiling at the turbo when switched off is pretty common, usually doesnt cause too many issues.

Check for leaks in the cooling system, a small leak can cause stuff like this.

Megane rs have an electronic pump that runs when engine is off to circulate the coolant which ive always assumed is for this issue. Personally not worth the aggro of fitting one though.

 

[Tommie_a]

Thanks, I was concerned it was going to cause an issue, appreciate the help 👍🏻

 

[R3k1355]

How are the coolant lines routed, some cars have a thermal syphon type system where the boiling water rises out of the core along one of the turbo lines and cool water is drawn into the core through the other.

 

[Tommie_a]

I’m afraid I’m not sure, I will have a look! I’m afraid I’m not too mechanically minded, I just like keeping them well serviced and clean 😬